Tree shear

ABSTRACT

A novel and improved tree shear adapted to sever a standing tree at ground level. The shear utilizes one stationary cutting blade and one movable cutting blade. The fixed cutting blade provides the reactionary force and cuts through one-half of the tree as the moving blade builds up force from its actuating cylinder to cut through the other half of the tree.

O Unlted States Patent 51 3,674,066 Shields 1 July 4, 1972 154] TREESHEAR 3,348,592 10/1967 Winblad et a1. ..144/34 E 3 230 988 1/1966 Dixon..144/34 E 72 1 t D W. h l 1 d 1 I 1 S 6 O 3,565,138 2/1971 Albright..144/34 R [73] Assignee: Owens-Illinois, Inc., Toledo, Ohio JunePrimary Examiner--G'erald DOSE Atto meyAlan J. Steger and E. J. Holler[211 Appl. No.: 45,313

[57] ABSTRACT [52] 11.8. CI E A novel and improved tree Shear adaptedSever a di g [5]] Illl. Cl ..A0lg 23/02 tree at ground level. The shearutilizes one Stationary i g [58] Flew of Search "144/2 3 34 34 309 ACblade and one movable cutting blade. The fixed cutting blade providesthe reactionary force and cuts through one-half of {56] References cuedthe tree as the moving blade builds up force from its actuating UNITEDSTATES PATENTS cylinder to cut through the other half of the tree.2,697,459 12/ l 934 McFaull ..144/34 E 4 Claims, 2 Drawing FiguresPATENTEDJUL 4 m2 3.674.066

sum 2 or 2 FIG. 2

INVENT OR.

DEAN \ldSmeuzs BY 5.3. HAM

AH-PIZNM TREE SHEAR BACKGROUND OF THE INVENTION This invention relatesto a novel and improved tree shear adapted to sever a standing tree atground level.

More specifically, this invention relates to a novel tree shear whichfeatures one fixed cutting blade and one movable cutting blade. Thistree shear is well suited to be utilized as an integral part of a treeharvesting apparatus such as that disclosed in my copending U.S. Ser.No. 45,314 filed June 11, 1970 and assigned to the same Assignee as thesubject invention.

Historically, trees have been felled by using hand saws manually,manipulated power saws, axes, wedges and guide ropes. These proceduresobviously require a considerable amount of manual labor. In order toreduce the amount'and cost of the manual labor various machines,including the tree harvester of my above-identified copendingpatentapplication, have been proposed. These machines all include heavy,cumbersome butt shear devices which have two movable cutting bladesactuatable to sever a standing tree. These existing butt shear devicesrequire two separate actuating systems which add considerably to theweight of the device.

It is, therefore, an object of this invention to provide a novel andimproved tree shear which overcomes the disadvantages associated withpreviously known tree shears.

SUMMARY OF THE INVENTION This invention provides a novel and improvedtree shear adapted to sever a standing tree at ground level.

In general, the tree shear of this invention utilizes one fixed cuttingblade and one movable cutting blade. The movable cutting blade ismounted on a pin which is an integral part of the fixed cutting bladehousing and is fastened to the tree harvesting apparatus of which thistree shear is an important component. The movable cutting blade isactuated by means of a hydraulically responsive system mounted withinthe fixed cutting blade housing. The fixed cutting blade provides thereactionary force and actually cuts through one-half of the tree as themoving blade builds up force from its actuating cylinder to cut throughthe other half of the tree. In order to effectively cut a tree as closeto ground level as possible, the cutting blades of the tree shear ofthis invention are offset below the center line of the actuatingcylinder. In addition, the pin about which the movable cutting bladerotates is eccentric in the area where it holds the movable cuttingblade to provide for adjustment of the edges of the cutting blades aswear is experienced.

Other objects, features, and advantages of this invention will becomeobvious upon reference to the following detailed description of theinvention and the drawings illustrating the preferred embodimentthereof.

IN THE DRAWINGS FIG. 1 is a perspective view of the improved tree shearof this invention.

FIG. 2 is a top view with parts broken away in section of the tree shearof FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION A tree shear incorporating thenovel features of this invention is shown in FIGS. 1 and 2 and isindicated generally by the numeral 10. The tree shear 10 includes a mainbody member 12 which is fastened to the front end portion 14 of a treeharvesting apparatus (not shown). The main body member 12 is formed inone solid piece but is comprised of a number of different componentparts. The main body member 12 includes an eccentric pin 16, a pair ofreinforcing flanges l8, and a fixed cutting blade frame 20. A pair ofstabilizing arms 22 are attached at one end to the reinforcing flanges18 and at the other end to the tree harvester (not shown). Thesestabilizing arms 22 serve to strengthen and stabilize the tree shear land to control its position relative to the front end portion. of thetree harvester. The fixed cutting blade frame 20 includes a fixedcutting blade edge 24 which is tapered and sharpened so as to be able toslice into and cut through a portion of the diameter of a tree 26.

Mounted for rotating movement on the eccentric pin 16 is a movablecutting blade frame 28. The movable cutting blade frame 28 includes amovable cutting blade edge 30 which is also tapered and sharpened so asto be able to slice into and cut through a portion of the diameter ofthe tree 26. Thus, when actuated the fixed cutting blade edge 24 and themovable cutting blade edge 30 are adapted to completely sever the trunkof a standing tree. It should be noted that both the fixed cutting bladeframe 20 and the movable cutting blade frame 28 are formed so as toinclude semi-circular portions 32 and 34, respectively, which defineopen areas above the cutting blades to provide a tree engaging andsupporting platform when the cutting blade edges 24 and 30 remain inmating engagement after severing a tree.

The movable cutting blade frame 28 includes an actuating socket 36formed on the diametrically opposite side of the eccentric pin 16 fromthe movable cutting blade edge 30. An actuating cylinder 38 for themovable cutting blade frame 28 is formed within the fixed cutting bladeframe 20. Mounted for reciprocating movement within the cylinder 38 is apiston 40 which in turn is connected to an actuating ball 42 positionedwithin actuating socket 36 in movable cutting blade frame 28 by means ofconnecting rod 44. Thus, reciprocating movement of piston 40 withincylinder 38 results in corresponding movement of ball 42 and rotation ofmovable cutting blade frame 28 about eccentric pin 16. The piston 40 isreciprocated relative to cylinder 38 by means of a reversible hydraulicfluid system shown schematically and indicated generally by the numeral46. The reversible hydraulic fluid system 46 includes a reversiblehydraulic fluid source 48 which is connected to the ends of cylinder 38on opposite sides of piston by means of hydraulic lines 50 and 52. Whenit is desired to rotate the movable cutting blade edge 30 into a closedposition in engagement with fixed cutting blade edge 24, reversiblehydraulic fluid source 48 is activated to pump hydraulic fluid throughline 50 into cylinder 38 to push piston 40 towards line 52 so that ball42 is forced against socket 36 to pivot movable cutting blade frame 28about eccentric pin 16 in the direction of the arrow shown in FIG. 1.Conversely, when it is desired to retract the movable cutting blade edge30 to the open position as shown in FIG. 1, the reversible hydraulicfluid source 48 is reversed to withdraw fluid from cylinder 38 throughlines 50 and pump the fluid into cylinder 38 through line 52 on theopposite side of piston 40. This reversing of the fluid causes piston 40to be displaced toward line 50 thereby pulling ball 42 in socket 36 topivot movable cutting blade frame about eccentric pin 16.

Pin 16 is eccentric so that the center of rotation of movable cuttingblade frame 28 is slightly displaced from the axis about which fixedcutting blade frame 20 would rotate if it were pivotable. Thus, whenmovable cutting edge 30 pivots into engagement with fixed cutting edge24 the outer extremity portions of each cutting edge engage before theinner portions meet. Hence, the eccentricity of pin 16 results in anonuniform mating of the cutting edges 24 and 30. However, this resultis very desirable in that it compensates for wear of the respectivecutting edges. Experience has shown that these outer extremity portionsof tree shear cutting edges wear down much more rapidly than do theinner extremities such that wom cutting edges never fully engage and thetree being cut is not completely severed. Thus, as the outer extremityportions begin to wear down the cutting edges of the tree shear of thisinvention continue to engage each other for a much longer period of timedue to the eccentricity of pin 16. Hence, the life of the respectivecutting edges is lengthened considerably and the necessity of frequentlyreplacing worn blades is eliminated.

It has been generally noted that in order to successfully cut a standingtree at ground level with hydraulic power, the cutting edges must be setbelow the center lineof the hydraulic cylinders. This arrangementresults in the development of high internal eccentric forces in theshear assembly. It has been found thatthese internal eccentric forcesare more easily controlled by the tree shear of the present inventionutilizing only one movable cutting blade and one actuating cylinder ascompared with previous shears which had two movable blades and twoactuating cylinders.

Thus, the present invention provides a unique'tree shear which, byvirtue of its having only one movable cutting blade, requires only oneactuating system and, therefore, is lighter in weight and moreeconomical thanpresently available tree shears. Further, by rotating themovable cutting blade about an eccentric pin the tree shear of thisinvention compensates for cutting blade edge' wear and considerablyincreases the useful life of the cutting blades.

1 claim:

l. A shear comprising:

a fixed frame means including a first cutting blade and an eccentric pinmeans;

a movable frame means pivotally mounted on said eccentric pin means onsaid fixed frame means and including a second cutting blade adapted tomove from an open position to a closed position-into engagement withsaid first cutting blade for cutting objects positioned between saidfirst and second cutting blades;

and actuating means mounted within said fixed frame means for movingsaid movable frame means and said second cutting blade to said open andclosed positions.

2. A shear as set forth in claim 1 wherein said actuating means includesa closed cylinder, a piston positioned for reciprocal movement withinsaid cylinder, a piston rod connected to said piston at one end and tosaid movable frame means at the other end, and a reversible source ofhydraulic fluid adapted to force hydraulic fluid against opposite sidesof said piston within said cylinder to move said piston relative to saidcylinder.

3. A tree shear comprising:

a fixed frame means including a first cutting blade and an eccentric pinmeans;

a movable framemeans pivotally mounted on said eccentric pin means onsaid fixed frame means and including a second cutting blade adapted tomove from an open position to a closed position into engagement withsaid, first cutting blade for completely severing a tree positionedbetween said first and second cutting blades;

and actuating means mounted within said fixed frame means for movingsaid movable frame means and said second cutting blade to said open andclosed positions.

4. A tree shear as set forth in claim 3 wherein said actuating meansincludes a closed cylinder, a piston positioned for reciprocal movementwithin said cylinder, a piston rod connected to said piston at oneendand to said movable frame means at the other end, and a reversiblesource of hydraulic fluid adapted to force hydraulic fluid againstopposite sides of said piston within said cylinder to move said pistonrelative to said cylinder.

1. A shear comprising: a fixed frame means including a first cuttingblade and an eccentric pin means; a movable frame means pivotallymounted on said eccentric pin means on said fixed frame means andincluding a second cutting blade adapted to move from an open positionto a closed position into engagement with said first cutting blade forcutting objects positioned between said first and second cutting blades;and actuating means mounted within said fixed frame means for movingsaid movable frame means and said second cutting blade to said open andclosed positions.
 2. A shear as set forth in claim 1 wherein saidactuating means includes a closed cylinder, a piston positioned forreciprocal movement within said cylinder, a piston rod connected to saidpiston at one end and to said movable frame means at the other end, anda reversible source of hydraulic fluid adapted to force hydraulic fluidagainst opposite sides of said piston within said cylinder to move saidpiston relative to said cylinder.
 3. A tree shear comprising: a fixedframe means including a first cutting blade and an eccentric pin means;a movable frame means pivotally mounted on said eccentric pin means onsaid fixed frame means and including a second cutting blade adapted tomove from an open position to a closed position into engagement withsaid first cutting blade for completely severing a tree positionedbetween said first and second cutting blades; and actuating meansmounted within said fixed frame means for moving said movable framemeans and said second cutting blade to said open and closed positions.4. A tree shear as set forth in claim 3 wherein said actuating meansincludes a closed cylinder, a piston positioned for reciprocal movementwithin said cylinder, a piston rod connected to said piston at one endand to said movable frame means at the other end, and a reversiblesource of hydraulic fluid adapted to force hydraulic fluid againstopposite sides of said piston within said cylinder to move said pistonrelative to said cylinder.